Consciousness

Consciousness is one of the most enigmatic phenomena of neuroscience and humankind in general. What are the neural processes that give rise to consciousness? Which processes are related to unconsciousness? Whereas consciousness was considered a non-scientific question for centuries, the last four decades have faced a wealth of computational and neuroscientific models proposed to explain consciousness. How good are these models and theories? To evaluate these theories, we subjected the major theories of consciousness to a systematic analysis using four explicit criteria including the small network argument (Herzog et al., 2007) and unfolding argument (Doerig et al., 2019). All models struggled at least with one criterion (Doerig et al., 2021). A book is forthcoming with Cambridge University Press.

Our of our main research topics is to understand unconscious processes. To this end, we developed paradigms where we can fully mask a target and prove it is indeed unconscious, which no previous paradigm achieved (only features of a target but not the target itself are unconscious in mask priming for example; Otto et al., 2006). We were able to show that the features of these elements are still visible at conscious elements and are, similar to the TMS experiment described in Decision making, stored and “influential” for a substantial period of time (Scharnowski et al., 2009).

Usually, we assume that consciousness is a smooth stream of percepts. However, continuous perception cannot explain most temporal phenomena, such as apparent motion, favoring discrete models. This leads to foundational questions about the temporal aspects of consciousness: What is the duration of a discrete percept? We can perceive apparent motion with 3ms differences. Is perception hence that quick? Other paradigms show much worse temporal resolution. We proposed a two-stage model of discrete perception and unconsciousness, where quasi-continuous unconscious processing precedes slow conscious perception (Herzog et al., 2016; Doerig et al., 2019; Herzog et al., 2020). In this line, we showed that perception is a sequence of discrete windows of integration, lasting about 300-450ms (Drissi-Daoudi et al., 2019). We provide a foundational introduction to these issues—ranging from philosophical issues in temporal consciousness to the debate between discrete and continuous models—in our upcoming chapter for the book Comprehensive Consciousness (Elsevier).